A call input device of an elevator installation, which comprises a control panel for generating electrical control signals for influencing the elevator control, is known from WO 2009/153386 A1. The control panel is a planar non-apertured plate with a plurality of touch-sensitive zones, each of which is associated with a respective one of a plurality of different control signals to be generated. Mounted on the control panel is at least one sensor which detects at the sensor the oscillations of the control panel generated by touching one of the touch-sensitive zones and transmits these to a computer unit. The computer unit compares the detected oscillation data with stored oscillation data, which was generated and stored at the time of a calibration process by touching each of the individual touch-sensitive zones. In the event of agreement of the instantaneously detected oscillation data with the stored oscillation data associated with a specific touch-sensitive zone the call input device generates a control signal which informs the control of the elevator installation that the specific touch-sensitive zone is activated.